Preparing Commercial Rooftop Units for Washington’s Rainy Season
A loose access panel or a worn door seal is easier to deal with before a week of rain than during a leak investigation. Commercial rooftop maintenance gives Washington building owners a chance to find those problems early and plan the work while roof access is easier. Around Seattle and Tacoma, a useful fall visit includes the cabinet, drainage, insulation, and the roof area around the equipment.
Start with panels, fasteners, and weather seals
Access panels need to sit squarely and stay securely fastened. Door gaskets can be torn or compressed even when a panel looks closed. A new rattle or a panel that has shifted is worth mentioning at the next visit so the technician knows where to look.
For example, the maintenance section of Trane’s IntelliPak rooftop manual calls for checking control-panel gaskets, exterior corrosion, loose access panels, and retaining screws. The exact procedure must follow your unit’s model-specific instructions. Do not treat a bead of sealant around every opening as a substitute for repairing the correct seal or panel.
Check the roof curb and surrounding roof
The equipment cabinet is only part of the picture. The curb supports the unit, and flashing protects the roof around the opening. Water can enter at that roof connection even when the cabinet itself is in good condition, so both areas need attention.
EPA’s moisture-control guidance includes checking roof penetrations, equipment weather seals, and curb flashing for gaps, loose sections, and corrosion. Have the HVAC contractor and roofing contractor coordinate where their work meets. Repairs should suit the roof system and its warranty requirements. Also identify who maintains surrounding roof drainage; that responsibility can otherwise fall between service agreements.
Separate condensate drainage from rainwater
Water around a unit is not always rainwater. A system providing cooling can still produce condensate in fall. Checking the pan, outlet, drain line, and trap helps the technician work out where the water is coming from and whether it is leaving the unit as intended.
Trane’s air-handler troubleshooting guidance identifies blocked drain lines, improper traps, and unit leveling as possible causes of standing or overflowing water. This illustrates why clearing one blockage may not resolve every drainage problem. Trap design and service procedures must match the specific equipment. Ask for the cause and corrective action in the report, rather than simply a note that water was removed.
Investigate corrosion and damaged insulation
Corrosion and deteriorated insulation deserve a closer look, including the condition of the material beneath the visible damage. The technician needs to establish which parts are affected and what repair is appropriate. A photograph can show a problem area, but it cannot confirm the condition of a hidden heat exchanger.
Damaged insulation also deserves attention. EPA’s moisture-control guidance explains the role of properly insulated cold surfaces in limiting condensation. Identify the material and its function before replacing it: insulation around cold piping and insulation near a heating section serve different purposes. Use materials and repair methods approved for that equipment. Covering a damaged area without investigating it can leave the underlying problem unresolved.
Keep outdoor-air openings working as designed
Preparing for rain should keep the unit’s airflow working properly. Outdoor-air hoods and openings need to be clear of debris, and their dampers and controls need to function. Covers that block ventilation, combustion air, or equipment discharge can create another problem instead of solving the first one.
PNNL’s economizer maintenance guidance includes inspecting exterior openings for obstructions and checking damper hardware, seals, and sensors. These items fit naturally into a seasonal visit. Our guide to commercial HVAC economizer inspections explains why moving parts and control checks matter alongside cleaning.
Plan safe access before scheduling rooftop work
Confirm roof-hatch or ladder access, building contacts, and any tenant restrictions when booking service. The contractor should plan the work around roof conditions and appropriate fall protection. Washington L&I’s seasonal-safety guidance highlights slippery surfaces and storm hazards. A forecast window is useful, but the conditions at the site determine whether rooftop work can proceed safely. Owners do not need to climb onto a wet roof to document a concern.
Record indoor symptoms after a storm
You can help a leak investigation without going onto the roof. From a safe indoor location, record when the water appeared, which room was affected, and whether the HVAC system was running. A photo and a short timeline help the contractors connect the symptoms with the conditions at the time.
Arrange prompt investigation of active leaks and wet materials. EPA’s moisture-prevention guidance emphasizes fixing water problems and keeping HVAC drainage clear. Painting over a stain or repeatedly wiping up water does not address its source. Keep people away from water near electrical equipment and have qualified personnel assess the affected area.
Make commercial rooftop maintenance actionable
A useful service report turns findings into a plan. It should identify the unit, show the concerns, explain what was completed, and name the remaining work. Knowing which items need prompt attention—and whether the roofer or HVAC contractor will handle them—makes follow-up much simpler.
For a broader service plan, read why regular commercial HVAC maintenance matters. MACLAF serves Seattle, Tacoma, and surrounding King and Pierce County areas. To arrange commercial rooftop maintenance or discuss a concern before rainy weather, contact MACLAF Heating & Cooling at (425) 999-1216.